Turbine-blade lashing



March 27, 1928,

1,663,563 J. L. RAY v TURBINE BLADE LASBING Filed Sept. 12. 1925 2Sheets-Sheet 1 W|TNE SE5: F" '3 INVENTOR aw/ 1: j A k BY W ATTORNEYMarch 27,192 1,663,563

7 J. L. RAY

TURBINE BLADE LASHING Filed Sept. 12. 1925 2 Sheets-Sheet 2 J.L.R.o

WITNESSES: Y INVENTORH BY AQW ATTORNEY Patented Mar. 27,1928.

UNIT ED STATES PATEN OFFICE.

JAMES RAY, or SWARTHMORE, PENNSYLVANIA, nssIeNon T0 WESTINGHOUSEnnncrnro & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TURBINE-BLADE LAsHINe.

Application-filed September 12, 1925.v Serial No. 56,039.

My invention relates to elastic fluid turbines more particularly to thebla-ding thereof and has for its'object the provision of an eflicientlashing for turbine blades which shall provide the maximum of stiffnessto the blading structure with a vminimum of resistance to motive fluidflowing through the blades.

Apparatus embodying features of my invention is illustrated in theaccompanying drawings, forming a party of this specification, in whichFig. 1 is a fragmentary sec tional view of a turbine blade carryingelement having a segment of blades mounted thereon provided with myimprovedulash- -ing; Fig. 2 is a fragmentary sectional View of twoblades having a modified form of my invention applied thereto; Fig. 318:1 sectional view, in plan, of the structure shown in Fig. 2; Fig. 4is a sectional view,

in plan, oftwo blades illustrating a furthermodification of myinvention; and Fig. 5 illustrates a method of lashing a segment ofblades in accordance with Fig. 4.

As is well understood in the turbine art, the function of blade lashingis to minimize as far as possible vibration of the blading. This isaccomplished by bracing the blades by means of one or more rowsoflashing soas to raise the natural period of vibration of the bladesabove, or out of harmony with that of the disturbing factors in turbineoperation which induce vibration. To give stiffness to the bladingstructure it isnecessary therefore thatthe lashing present a maximum ofresista-nceto bending in the plane of vibration. \Vhile it would beentirely possible to provide a single lashing member sufliciently heavyto perform this function, its practical application is under certaincircumstances impracticable. If a round lashing wire of sufficientdiameter is employed, the resistance to motive fluid flow through theblades is increased and the eiliciency of the turbine is impaired. Onthe other hand, if a lashing member of relatively small section in thedirection of motive fluid flow and flattened across the face of theblade is employed, its. attachment to the blades is expensive andtedious and its. moment of resis ance or stiffening effect isvlow inproportion to its bulk. Confronted with these difficulties the turbine,designer has lly provided a blade lashing which is a compromise as tostrength and impedance lashing wires drawn together and joined.

intermediate the blades of a row, or may be in the form of individualrings or links applied to each blade in the process of manufacture andjoined together intermediate the blades upon assembly. With either form,the minimum of resistance to motive fluid flow is effected, togetherwith a maximum of resistance to flexure and hence to vibration.

Referring now to the drawings for a better understanding of myinvention, I show in Fig. 1 at 10 a fragment of a blade carryingelement, for example, a turbine rotor, having a segment of five bladesl111 mounted thereon. The blades 1111 are tied together by means oftwolashing wires 12 and13 inserted in suitable holes 14 and 16 provided inthe blades. Intermediate the blades 11-11 the lashing wires 12 and 13are drawn together, as at 1717 and joined to each other, preferably byfusion of metal, such as welding, soldering or lmazing.

In applying the form of lashing indicated in Fig. 1, the lashing wiresare threaded through the holes 14 and 16 in theblades 11 upon assemblyof the blades in the blade holding element. The lashing wires n'iay thenbe drawn together, as at .17, and secured in the manner set forth.Preferably the lashing wires 12 and .13 are secured to the blades 'l1l1,thus adding additional stiffness to the structure. Themanner of securingthe wires 12 and to the blades may be any known to those skilled in, theart.

In Figs. 2 and 3 I show a modified form of my invention wherein theblades 111l are provided with holes 14 and 16, as pre viously shown.However, in this modification I provide individual lashing members 18-1S in the form of split rings or links which are applied to the bladesin the process of manufacture and closed as at 19.

n at

The outer ends of the links may be reduced in thickness on alternatesides, as shown at 21-21 in Fig. 3, so that upon assembly the outer endsoverlap each other intermediate. the blades. Upon assembly, theoverlapping portions of the rings are joined together by fusion of.metal, as at 22, thus providing a sturd unitary structure.

In Fig. & I show a further modification in which the reaction blades11ll are provided with holes 26-26 which are normal to the axes of leastresistance of the blades, said axes being indicated at arr-(t. Insertedin the holes 26-26 are lashing members 27 similar to the members 18illustrated in Fig. 2 except that the angular relation of the blades toeach other permits the ends to overlap as shown, facilitating assemblyand removing the necessity of flattening the ends as shown in Fig. 2. Myimproved lashing, applied in this manner gives the greatest resistanceto fiexure of the blading.

Referring now to Fig 5, I show a method of lashing a segment of blades,particularly applicable to the modification of my invention shown inFig. 4c and also particularly applicable to short reaction bla'dingwhere there is limited room between the blades for the insertion ofsoldering or weld ing tools. In accordance with this method, a se -meritof blades 11-ll is mounted in a suitable base 28 made of insulatingmaterial and conforming in contour to the blade holding element in whichthe blades are to be finally inserted. Interposed between each of theblades 1l11 at the roots thereof is a spacing member 29 also made ofinsulating material. After mounting in the manner shown with the lashingmembers 2727 overlapping between blades, and in contact, electrodes 81and 32 of an electric welding apparatus are connected to the lashingmembers 27 at opposite ends of the segment and suit-able pressureapplied to each joint, if necessary, after a welding temperature isreached. The several lashing members are thus welded togetherintermediate the blades without subjecting the blades to theWeldingheat. After welding, the blades and spacing members are removedfrom the base 28 and the blades with permanent spacing members arepermanently mounted in a blade holding element.

It should be noted that in each form of my invention no lashing membergoes directly across from blade to blade, but that a. more or lessindirect or serpentine route is followed. Thus, upon heating andcooling, the lashing may deflect slightly and remain tightly attached tothe respective blades, at the same time having suflicient rigidity toeifectually prevent vibration.

From the foregoing it will be apparent that I have devised an improvedlashing neeases means for turbine blades effective for resisting, to amaximum degree, flexure of the blading in service, simple ofconstruction and easy of application.

"While I have shown my invention in several forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications, without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are imposed by the prior art or as arespecifically set forth in the appended claims.

What- I claim is:

l. Lashing means for turbine blades comprising cooperating lashingmembers secured at two points to a blade and joined togetherintermediate adjacent blades in a row.

2. Lashing means for a row of turbine blades having at least two seriesof aligned holes, comprising lashing members inserted in the holes andjoined together intermediate adjacent blades.

3. In a turbine, a row of blades having an inner and an outer series ofaligned holes, lashing members inserted in the holes and joined togetherintermediate the blades by fusion of metal.

at. In a turbine, a row of blades having an inner and an outer series ofaligned holes, lashing members inserted in the holes, secured to theblades and joined together intermediate the blades by fusion of metal.

5. In a turbine, a row of blades, individual lashing members secured toeach of the blades normal to the axis of least resistance thereof andjoined together intermediate adjacent blades in a row. I

6. In a turbine, a row of blades havins an inner and an outer series ofaligned holes, individual lashing members comprising links having aportion extending through each of the holes and secured to each of theblades, and means joining the lashing members to gether intermediateadjacent blades.

7. In a turbine, a row of blades having an inner and an outer series ofaligned holes, individual lashing members comprising links having aportion extending through each of the holes normal to the axis of leastresistance of the blades and secured to the blades, and means securingthe lashing members together intermediate adjacent blades.

8. In a turbine, a. row of blades, lashing members therefor each securedto at least two places on a blade, extending indirectly to an adjacentblade and joined to another lashing member intermediate the blades.

In testimony whereof, I have hereunto subscribed my name thistwenty-seventh day of August, 1925.

' JAMES L. BAY,

